Wild lobsters cannibalize the small, weak, says biologist

Increasing ocean temperatures could be a factor, says U.S. scientist

A new study documents cannibalistic behaviour by lobsters in the wild for the first time, according to an American scientist — but some doubt whether this is new information.

Noah Oppenheim, a graduate student at the University of Maine, said climate change may be a factor in increasing reports of cannibalistic behaviour among wild lobsters.

"It has never been noted in the literature, previous to my experiments, that individual lobsters will consume others in the wild," he said.

In captivity, lobsters can be aggressive and have been known to snack on their sick or dead peers.

Larger lobster cannibalizing a young lobster tethered during experiment. (CBC)

Those rubber bands are not only for human fingers — they're also to protect lobsters from one another.

Oppenheim found that wild lobsters will make a snack out of smaller lobsters, given the chance.

"The tethered juvenile lobster at night was consumed readily by the larger predators," said Oppenheim.

"So, when you immobilize them, they stand little to no chance. Lobsters were 93 per cent likely to be eaten during the night time."

But Marc Lanteigne, with the Department of Fisheries and Oceans, said the experiment does not reflect reality, since juvenile lobsters are not usually tied up.

"Usually these lobsters, which were quite small, are just a few years old — are well hidden on the rocks and in gravel. Normally if they venture out, if they see a predator, which may include a lobster, a big lobster, they will hide or swim away, walk away," said Lanteigne.

Carl Allen has been been fishing lobster since he was seven years old. He now works in carpentry because the recent lobster glut has taken a toll on the industry, driving the prices down.

He says this cannibalism is normal behaviour for lobsters.

"The stock is at a level now, is about the highest levels they've ever been, that we've ever noticed. There's more of them so you might be noticing it more because there's more lobsters on the bottom," said Allen.

When it comes to the effect of climate change on the Atlantic ecosystem, Oppenheim said this finding was just a piece of the puzzle.

Increased cannibalism or not, all three men did agree that the rising sea temperature is changing the landscape for lobsters.